1. Field of Invention
The present invention relates to technical field of cardiac medical instruments, and more particularly to a balloon dilatation catheter provided with soft coating tip.
2. Description of Related Arts
In the medical field, the percutaneous transluminal coronary angioplasty has become mature gradually. As the key mechanical devices of this technology, the balloon dilatation catheters have been upgraded fast with the development of the technology. The PTCA process typically comprises advancing the guiding catheter via skin penetrating within the femoral artery or skin artery so as to address the distal end of the guiding catheter at the entrance of coronary artery, after locating the guiding artery, guiding a balloon dilatation catheter to pass through the guiding artery into the coronary artery, wherein the balloon dilatation catheter generally is used with a small-diameter operative guide wire which can be operated to enter into the selected artery branch to be cured, and then transferring the balloon dilatation catheter which is in a shrinking state together with the anastomotic guide wire to a constricted area, and finally inflating the balloon 1 to expand the constricted artery for purpose of cure.
Currently, a conventional catheter tip 3 of the PTCA balloon dilatation catheter in the market generally employs a structure in which an inner catheter 2 is directly weld to the catheter tip 3, wherein a prolonged section it of the balloon 1 is used for coating the connection thereof prior to the welding process. The current tips are divided into two groups in concern of the selected material: one is soft tip, and the other is relatively hard tip. The soft tip is advantageous for its good softness and being resulting in less injury to a blood vessel. Since its good adhering ability with the guide wire, the flexibility of the dilation catheter is effectively enhanced and thus currently the soft tip serves as the main tip material. The shortcomings of the soft tip in use are also obvious. The inner catheter and the tip both uses soft materials, even if the interior of the catheter and the guide wire are all coated with lubricating layers, but the soft material of resilient feature has a strong coating ability and may easy to result in a dead lock when the catheter is exerted with a relatively large force at a corner, thus the guide wire cannot rotate freely and most often the surgery simply cannot go on. When the relatively hard tip is used, the most vital to disadvantage is that it may result in a wound to the blood vessel tissue and cause a further injury to the cardiovascular system of the patient.